.app {
  padding-top: 50px;
}

.nav {
  display: flex;
  justify-content: center;
  align-items: center;
  position: fixed;
  left: 0;
  top: 0;
  z-index: 99;
  width: 100%;
  height: 50px;
  background: #fff;
  box-shadow: 0 0 10px rgba(0, 0, 0, .5) ;
}

.nav-item {
  display: flex;
  justify-content: center;
  align-items: center;
  flex: 1;
  height: 100%;
}

.nav-item.active {
  color: #00f;
}

.layout {
  user-select: none;
}

.layout-item {
  position: relative;
  line-height: 50px;
  text-align: center;
  border: 1px solid #000;
  cursor: pointer;
}

.layout-item::before {
  content: attr(data-type);
  position: absolute;  
  left: -1px;
  top: -1px;
  z-index: 9;
  padding: 0 4px;
  height: 20px;
  line-height: 20px;
  font-size: 10px;
  border: 1px solid #000;
  background: #fff;
}